For years I've been wanting to create a tablet like device based on a SoM (System on Module). Doing something from scratch, routing DDR3 RAM, eMMC etc. didn't seem realistic to me, this is not only really hard but also very expensive. So SoM it is, which comes with the additional benefit of user upgradability if the SoM manufacturer stays true to their pinout with successor products, which they usually do if the SoM is in any way meant for an industrial market.
Back then I started out with the Raspberry Pi compute module but the more I thought about my specs the clearer it was to me that it just wont cut it.
I wanted something that can run modern applications, something that is actually very usable and is not just a cool thing on paper.
The past years I've been looking around for affordable SoMs that offer enough performance to be viable, until now there were either cheap outdated SoMs or ones that mainly target the industrial market and are too expensive.
In recent months there is finally an interesting selection of SoMs out there.
Technexion/Wandboard released the Pico SoM product range and the Pico Pi as a dev board. They range from 72-150$ For 150$ you get a fairly decent ARM SoC with 4K video support, 4GB RAM, 16GB eMMC and 802.11 AC WIFI and Bluetooth 5.0.
Essentially the basic specs for a modern tablet.
The other SoM that just popped up recently is the Nvidia Jetson Nano. Very capable SoM with similar specs but lacking WIFI. Though the GPU is much more high-end than the iMX8M Quad.
Another very important part is the Display. Until now I never found a satisfying product that had a good picture quality and resolution. It just feels wrong to use a 800x480 display in 2019.
For some reasons there are really great IPS displays popping up all over the place from 1.8" to 13" there is something in every category and all of them can be considered to be "retina" displays. If I want to make a tablet I don't want it to feel like tech from 10 years ago.
So the goal is to make it good or go home :)
What this project will then essentially entail is to design a carrier board for one the two SoMs (though I want to see if I can keep it generic enough to allow for different SoMs in the future) and create a mechanical design that will fuse display and carrier in a visually pleasing way while maintaining the goal of hardware modularity end reusability.
My MVP will have the following specs:
- Fast enough SoC/SoM to run a modern web app without lag.
- Enough RAM for more demanding applications >=2GB
- 802.11AC Wifi and Bluetooh
- USB for charging and data >=USB2.0
- High-res display in the 7-10" range connected via MIPI DSI or eDP.
- Modular peripherals, the carrier should be very small allowing different peripheral connectors to be attached through FFC cables. A choose your own peripheral kind of product.
- A parametric case design that allows for different screen sizes and peripheral openings.
- Battery and charging circuit. No idea how large but I aim for around 4h+ active usage for now.
- Extensible storage via SDcards
Cool things for the future:
- USB-C PD
- Desktop peripherals that you never see in mobile products like an Ethernet Jack.
- mPCI-E connector ( I never touched PCI-e so lets see how that goes). This would technically also allow for M.2 and adding a proper SSD to your tablet.
- This does not have be a tablet, if I can make it small enough a phone is also possible, at least a phablet.
- USB 3.0+
- LTE either through USB or PCI-E
- Keyboard "dock" to turn it into a Laptop
Here is a block diagram of what I'm looking to develop, this might change slightly in the future as the design progresses.
Visualization Images Courtesy of: